Could Pure Electrics Emit More Than Hybrids?

Jeremy Michalek says the biggest electric vehicle subsidies are going to the wrong cars. After studying the life cycle of electrified cars -- from the first moment of raw material mining to the final day in the car's life -- Michalek and fellow researchers have concluded that hybrids with smaller batteries pollute less than pure EVs.

That, of course, flies in the face of everything we now believe. Today, cars with bigger lithium-ion batteries receive three times as much in federal subsidies than hybrids with smaller batteries. Those subsidies, however, are based on the idea that big-battery EVs pollute less, which may not necessarily be so, Michalek says.

A battery electric vehicle (shown as "BEV240") could be responsible for more social damage in the form of emissions than a plug-in hybrid, largely as a result of battery size. (Source: Carnegie Mellon University)

"As the battery pack gets larger, the emissions associated with manufacturing can be quite significant," Michalek, an associate professor of mechanical engineering and public policy at Carnegie Mellon University, said in an interview. "You have to look at the entire supply chain. Some of the emissions come from the facility where the battery is assembled, but a portion of it is upstream. Some of it comes from the powerplants used to create the electricity that runs the equipment."

The gist of the studies' conclusions is that there's more to emissions than what comes out of the tailpipe. This is especially so when it comes to vehicles with big lithium-ion batteries. According to the studies, a battery-electric car with a 240 km (144 mile) range is responsible for between $4,000 and $5,000 worth of "social damages" over its lifetime. The figure is similar to conventional gas-burning vehicles, but higher than that of hybrids.

A plug-in hybrid with a 20 km (12 mile) all-electric range, for example, comes in at less than $4,000. In arriving at the numbers, researchers considered emissions caused by vehicle operation, as well as by electricity production, gasoline production, battery production, and vehicle production.

The bottom line of the study is that smaller battery size is important. Although the studies didn't mention any specific vehicle models, their findings indicate that a Prius PHV plug-in hybrid with a 4.4 kWh battery would emit less than a Chevy Volt with a 16 kWh battery. Similarly, a Volt would emit less than a pure electric car with a big battery.

This analysis is fundamentally and very deeply flawed. It presumes that the mix of fuels used for generating electricity will remain as it is now, heavily fossil fuel based. It presumes that the pollution produced by large fossil fueled electric power plants is in every way similar to that produced by smog belching car engines. I have no idea how the "battery" manufactur pollution figure was developed. And no idea how the total for vehicle lifetime, including maintenance et al fits with these doctored figures. Design News should take more care in presenting such flawed analysis. Need at least a better peer review and a researched counter position.

A very interesting article.Not really surprising to me, the energy density of liquid fuels is factors above that of existing batteries and for a very long period of time will also outnumber future batteries. So we allways have to consider the balance of cost and benefit of measures we plan to save the planet. Hybrid technology could be one keyelement.From the engineering standpoint, the most important and first approach should be, to develop technologies that are able to produce liquid fuels from sunlight or uneatable plants or bacterias. If we are talking about EVs then we allways have personal cars in mind. Has anyone ever calculated the size and cost of a battery to supply a 40tons truck or a 100ktons train in aereas where no electricity is available? Some scientists from israel published in the late 80s some datas about the influence of oil shortage onto the structure and survival rate of big american cities. Those cities are not able to survive if the oil is empty, because they can not further be supplied, with food, water, energy and cannot be diposed from gargage any more. Dreaming of a future just based on photovoltaic and wind energy will provoke heavy changes of our daily life and infrastructures we know today. Also if we are talking about clean energy and footprint, we should consider how all the money is earned ( produced) to support the development of clean technology and what will be the amount of benefit, money efficiency which equals CO2 at the end of the process.

One item that hasn't been addressed yet is whether the battery cells will be completely recyclable. How much will it cost to replace the bed of cells for these vehicles if they want to typically get 10 to 15 years wear from them? Will this impact the waste landfills, etc.?

One additional issue is the rate of affordability. Since MPG is becoming a factor that doesn't really apply well across the field, why doesn't the industry create a new rate based on total cost per mile? DPM (dollars per mile) would make much more sense to me while we're in this transition period. Include the cost of the vehicles as well.

This makes total sense to me. Any technology requiring so much government subsidy money is a technology that is not ready for normal day-to-day use yet. When EVs make sense without a subsidy, then they will make sense. Not before.

At the very least, almost every component of cost comes back to the environmental impact of producing energy. It certainly does assume that electricity will continue to be as dirty as it was 10 years ago and that in future will return to that high level which is a rather pessimistic (or as Romney would have it, optimistic) view. Curiously, the energy cost associated with making a large EV battery (150 mi driving distance for an unspecified size of vehicle) would be approximately 2.5 times the energy cost of making the entire rest of the vehicle - one would like to see where that data comes from: at least the MSRP of the battery should be less than the industrial price of the energy input ... you'd think. In this analysis, it appears that it takes more energy to make the battery than the battery will ever store!?

To be fair to the author, this is the pessimistic view where we return to dirty electricity as in the heyday of 51% coal, nothing of any value occurs in either basic battery technology or battery manufacturing technology and EVs never achieve economy of scale compared to IC vehicles. At the extremes of this problem set we can either give up or get our collective buts in gear or just wait for the Japanese to do it for us. Any one who assumes that battery technology is static would be incorrect (even in the humble LA family of batteries). Another emerging technology is all electric drive trains which will have a substantial impact on EV efficiency. However, the worst thing to bet against is manufacturing technology which is financially purely a scale factor - given the right context, manufacturing and process engineers can squash production costs like a bug. Perhaps the one fallacy of this study is to compare the costs of various technologies at significantly different points on the experience curve without adjusting for experience factors.

It's more than simply reducing pollution and increasing electrical energy generation and transmission efficiency. To be more to the heart of environmental protection we have to learn better ways to produce the materials of the future. Use far less energy, pollute less and fine tune processes so they do not create toxic waste.

For example, if a process requires a lot of heat, why not build a facility around solar furnaces? Granted this would restrict the facility geographically and add to transportation costs. But looking into the future, transportation will become much more energy efficient, but, of course, only if we continue to work on all fronts to raise the efficiency of the new industrial age.

In the consumer realm I'm still coming across new products that have been designed with zero consciousness about energy waste. The old phonograph turntable is back as a relatively cheap consumer comodity selling at a fraction of the cost of the technology of a couple of decades ago. The turntable, typically of a cheap lightweight plastic base, has tone arm and RIAA equalized phono cartridge pre-amplifier built in! Furthermore, most of this new breed includes a built in USB sound card (A/D converter) so that old vinyl can be dubbed directly into a computer as an MP3 sound file for transfer to a personal audio player. Problem is, there is no On/Off power switch. Only the turntable motor is switched, typically by placing the tone arm on the record. Round the clock, the electronics remains powered. Granted its only a few watts, but multiply it by millions of households with great vinyl album collections and this wasted energy isn't trivial.

Electric makes real sense when the source of the electricity is connected directly to the vehicle as is done with electric trains. Then the battery contribution is removed from the graph and a pure electric has very low social impact. So a hybrid with a caternary or some other form of efficient connection would be the best. Regen braking would feed power back into the grid.

Its about bloody time we start looking at energy consumption for the entire life of the car, not just for the operation of the vehicle. A "zero emission vehicle" is a myth -- the emissions have to happen somewhere if energy is required -- for operation or for manufacture.

In addition, and the auto manufacturers won't like this, but it would be nice to see real studies of the overall energy effect of keeping a car longer than the, what is it now, 2-3 year average?

Heartening to see? When hybrids were first introduced about 8 to 10 years ago, they were victimized by ICE drivers as slow, inefficient, didn't make economic sense etc. etc. It seems we are running into the same arguments with BEVs. There was an incentive for early adopters by giving tax breaks etc for buying these cars. Battery technology is not static and as more sources of electrictity are used such as nuclear, solar PV, wind etc. the only component of manufacturing and operation of these vehicles related to pollution will be the battery manufacturing and recycling of it. Captive power plants can have their pollutions managed much more efficiently than millions of ICE vehicles belching varying amounts of pollutants. Getting one of the 1970s or 1980s ICE vehicles is probably equivalent to hundreds of modern day ICE cars. Let's get rid of all these belchers first. So, do people consider the transportation costs/pollution with gasoline, oil exploration, wars and so on so forth? How about engine lubricants, various other consumables related to ICE? This is a BS article at best with only part of the story. Many of us are using solar panels to feed power back into the grid, reducing the need for grid upgrades at the same time providing power to charge EVs. Distributed power generation and usage. It is actually heartening to see that there are some who will look to the future and try to advance the technology rather than sit and complain about the tax subsidies or find reasons to kill a technology in its infancy.

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